/*
 * Copyright 2005 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 
package org.wamblee.photos.servlet;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.wamblee.photos.model.Album;
import org.wamblee.photos.model.Photo;
import org.wamblee.photos.model.PhotoEntry;

/**
 * Sends an image (either thumbnail or full size) from the photo album.
 * 
 * The returned picture is defined based on {@link javax.servlet.http.HttpServletRequest#getPathInfo}. 
 * as follows. If the path info starts with the string defined by {@link #THUMBNAIL_NAME}, then 
 * a thumbnail image is served and the rest of the path info is the relative path of the 
 * picture. Otherwise the path info is identical to the relative path of the picture. 
 */
public class ImageSender extends HttpServlet {
	
	static final long serialVersionUID = 4069997717483260853L;
	
	/**
     * Name of the request parameter indicating that a thumbnail must
     * be viewed
     */
    public static String THUMBNAIL_NAME = "thumbnail"; 

    /*
     *  (non-Javadoc)
     * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

    /*
     *  (non-Javadoc)
     * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
	protected void doPost(HttpServletRequest aRequest,
			HttpServletResponse aResponse) throws ServletException, IOException {

		String entryPath = aRequest.getPathInfo();
		if (entryPath == null) {
			entryPath = "/";
		}
		boolean thumbnail = aRequest.getParameter(THUMBNAIL_NAME) != null;
		if ( entryPath.startsWith("/thumbnail")) {
			entryPath = entryPath.substring("/thumbnail".length());
			thumbnail = true; 
		}
	
		Album root = new PhotoSession(aRequest.getSession()).getAlbum(); 
		PhotoEntry entry = root.getEntry(entryPath);

		Photo photo = (Photo) entry;
		InputStream is; 
		if (thumbnail) {
			is = photo.getThumbNail();
		} else {
			is = photo.getPhoto();
		}
		sendImage(aResponse, is);  
	}

	/**
     * Sends the image. 
	 * @param response Response
	 * @param is Input stream of the image.
	 * @throws IOException In case an IO problem occurs. 
	 */
	private void sendImage(HttpServletResponse response, InputStream is)
			throws IOException {
		int c;
		while ((c = is.read()) >= 0) {
			response.getOutputStream().write(c);
		}
	}
}